21168309647 has 8 divisors (see below), whose sum is σ = 22210712160. Its totient is φ = 20136077280.

The previous prime is 21168309641. The next prime is 21168309661. The reversal of 21168309647 is 74690386112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21168309647 - 2⁸ = 21168309391 is a prime.

It is a super-2 number, since 2×21168309647² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21168309641) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2538272 + ... + 2546597.

It is an arithmetic number, because the mean of its divisors is an integer number (2776339020).

Almost surely, 2^21168309647 is an apocalyptic number.

21168309647 is a deficient number, since it is larger than the sum of its proper divisors (1042402513).

21168309647 is a wasteful number, since it uses less digits than its factorization.

21168309647 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5085073.

The product of its (nonzero) digits is 435456, while the sum is 47.

The spelling of 21168309647 in words is "twenty-one billion, one hundred sixty-eight million, three hundred nine thousand, six hundred forty-seven".